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Patent US5567484A successfully refreshed from Google Patents.
US5567484A
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Process for texturing brittle nonmetallic surfaces
Assignee: HGST Netherlands BV
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Filing: 1995-05-31
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Granted: 1996-10-22
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Expires: 2015-05-31
Abstract
Abstract A process for creating an array of bumps to texture a brittle nonmetallic surface, such as a glass substrate for data recording disks. The texturing process uses a laser to provide pulses of proper energy fluence to the brittle glass surface to produce a plurality of raised bumps in the surface. The bump creation is accomplished without unwanted micro-cracking or ejection of surface material by limiting the laser pulse fluence to a value in a narrow operating region discovered below the abrupt thermal shock fluence threshold for the brittle nonmetallic surface material. The process is also applicable to other brittle surface textures, such as those intended for use as "stamping surfaces" for the contact reproduction of the negative of a surface pattern, such as an optical disk.
Inventors
- 👤 Peter M. Baumgart
- 👤 Wing P. Leung
- 👤 Hung V. Nguyen
- 👤 Thao A. Nguyen
- 👤 Andrew C. Tam
- 👤 Anthony Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:51
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/8408; B; B23; B23K; B23K26/00; B23K26/18; B23K26/352; B23K26/355; B23K26/36; B23K26/40; C; C03; C03C; C03C23/00; C03C23/0005; C03C23/0025; G11B5/8404; B23K2103/00; B23K2103/16; B23K2103/50; B23K2103/52
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
262 words
A method for texturing a surface comprising the steps of: providing an element which is composed essentially of a glass material which has a thermal shock threshold fluence level above which said glass material is fractured, the element having a surface; concentrating pulses of laser energy selectively on a plurality of spaced-apart locations over a treatment area of said surface to alter the topography of said surface in a target area at each said spaced-apart location, each pulse of laser energy having a fluence f p at said each spaced-apart location wherein the fluence f p is less than said thermal shock threshold fluence level for said glass material; each pulse of laser energy having laser energy E p a duration t p and a focussed spot having a maximum spot diametral dimension D p , wherein E p , t p and D p are selected to limit said fluence f p to a value below said thermal shock threshold fluence level, whereby a bump is formed in said each target area, said each bump having a maximum bump diametral dimension D d and rising to a maximum height h d above said surface; and said duration t p being in the interval 10 -9 to 10 -1 seconds, said maximum spot diametral dimension D p >D d being in the interval 1 to 500 micrometers and said pulse of laser energy having a wavelength λ p such that the optical penetration of said pulse of laser energy in said surface is in the interval 10 -8 to 10 -3 meters.
Claim 2
Independent Claim
262 words
A method for texturing a surface comprising the steps of: providing an element which is composed essentially of a glass material which has a thermal shock threshold fluence level above which said glass material is fractured, the element having a surface; concentrating pulses of laser energy selectively on a plurality of spaced-apart locations over a treatment area of said surface to alter the topography of said surface in a target area at each said spaced-apart location, each pulse of laser energy having a fluence f p at said each spaced-apart location wherein the fluence f p is less than said thermal shock threshold fluence level for said glass material; each pulse of laser energy having laser energy E p a duration t p and a focussed spot having a maximum spot diametral dimension D p , wherein E p , t p and D p are selected to limit said fluence f p to a value below said thermal shock threshold fluence level, whereby a bump is formed in said each target area, said each bump having a maximum bump diametral dimension D d and rising to a maximum height h d above said surface; and said duration t p being in the interval 10 -9 to 10 -1 seconds, said maximum spot diametral dimension D p >D d being in the interval 1 to 500 micrometers and said pulse of laser energy having a wavelength λ p such that the optical penetration of said pulse of laser energy in said surface is in the interval 10 -8 to 10 -3 meters.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said maximum bump height h d is in the interval 1 to 1000 nanometers.
Claim 4
Dependent Claim
44 words
The method of claim 1 wherein said surface strongly absorbs laser energy in a first spectral region and said wavelength λ p is in said first spectral region and said pulses of laser energy are generated by a carbon dioxide (CO 2 ) laser.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D s ≧D d .
Claim 6
Dependent Claim
55 words
The method of claim 1 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D s substantially less than said maximum diametral dimension D d , whereby a plurality of said bumps merge with their neighboring bumps to form a substantially continuous ridge on said surface.
Claim 7
Dependent Claim
20 words
The method of claim 1 including the step of depositing on said surface a film of magnetic data recording material.
Claim 8
Independent Claim
203 words
A method for texturing a substrate composed essentially of a glass material comprising the steps of: providing a substrate composed essentially of a glass material which has a thermal shock threshold fluence level above which said glass material is fractured, the substrate having a substrate surface; concentrating pulses of laser energy selectively on a plurality of spaced-apart locations over a treatment area of said substrate surface to alter the topography of said substrate surface in a target area at each said spaced-apart location, each pulse of laser energy having a fluence f p at said each spaced-apart location, wherein the fluence f p is less than said thermal shock threshold fluence level for said glass material; and each pulse of laser energy having energy E p a duration t p and a focussed spot having a maximum spot diametral dimension D p , wherein E p , t p and D p are selected to limit said fluence f p to a value below said thermal shock threshold fluence level whereby a bump is formed in said each target area, said each bump having a maximum bump diametral dimension D d and rising to a maximum height h d above said substrate surface.
Claim 9
Independent Claim
203 words
A method for texturing a substrate composed essentially of a glass material comprising the steps of: providing a substrate composed essentially of a glass material which has a thermal shock threshold fluence level above which said glass material is fractured, the substrate having a substrate surface; concentrating pulses of laser energy selectively on a plurality of spaced-apart locations over a treatment area of said substrate surface to alter the topography of said substrate surface in a target area at each said spaced-apart location, each pulse of laser energy having a fluence f p at said each spaced-apart location, wherein the fluence f p is less than said thermal shock threshold fluence level for said glass material; and each pulse of laser energy having energy E p a duration t p and a focussed spot having a maximum spot diametral dimension D p , wherein E p , t p and D p are selected to limit said fluence f p to a value below said thermal shock threshold fluence level whereby a bump is formed in said each target area, said each bump having a maximum bump diametral dimension D d and rising to a maximum height h d above said substrate surface.
Claim 10
Dependent Claim
26 words
A method as claimed in claim 7 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
Claim 11
Dependent Claim
40 words
A method as claimed in claim 7 wherein said duration t p is in the interval 10 -9 to 10 -1 seconds and said maximum spot diametral dimension D p >D d is in the interval 1 to 500 micrometers.
Claim 12
Dependent Claim
44 words
A method as claimed in claim 9 wherein said pulse of laser energy has a wavelength λ p such that the optical penetration of said pulse of laser energy in said glass material is in the interval [10 -8 , 10 -3 ] meters.
Claim 13
Dependent Claim
26 words
A method as claimed in claim 10 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
Claim 14
Dependent Claim
21 words
A method as claimed in claim 7 wherein said maximum bump height h d is in the interval [1, 1000] nanometers.
Claim 15
Dependent Claim
44 words
A method as claimed in claim 7 wherein said pulse of laser energy has a wavelenth λ p such that the optical penetration of said pulse of laser energy in said glass material is in the interval [10 -8 , 10 -3 ] meters.
Claim 16
Dependent Claim
31 words
A method as claimed in claim 13 wherein said glass material strongly absorbs laser energy in a first spectral region and said wavelength λ p is in said first spectral region.
Claim 17
Dependent Claim
26 words
A method as claimed in claim 14 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
Claim 18
Dependent Claim
40 words
A method as claimed in claim 15 wherein said duration t p is in the interval 10 -9 to 10 -1 seconds and said maximum spot diametral dimension D p >D d is in the interval 1 to 500 micrometers.
Claim 19
Dependent Claim
30 words
A method as claimed in claim 16 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D s ≧D d .
Claim 20
Dependent Claim
26 words
A method as claimed in claim 17 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
Claim 21
Dependent Claim
59 words
A method as claimed in claim 16 wherein each said spaced-apart location is separated from the nearest neighboring said spaced-apart location by a spacing distance D s substantially less than said maximum bump diametral dimension D d , whereby a plurality of said bumps merge with their neighboring bumps to form a substantially continuous ridge on said substrate surface.
Claim 22
Dependent Claim
26 words
A method as claimed in claim 19 wherein said substrate is composed essentially of a glass base covered with a film of magnetic data recording material.
Claim 23
Independent Claim
141 words
A method of texturing a surface of an element comprising the steps of: providing a non-metallic brittle element which has a surface, the surface having a nominal surface plane; directing a plurality of laser pulses at a plurality of locations on the surface of the element, each laser pulse having a fluence f p and a duration t p at a respective location on the surface of the element; the element having a threshold thermal fluence level at each location above which the element shatters and/or results in material ejection; and each laser pulse having a fluence f p and duration t p which is selected to produce a bump of diameter D d and a height h d above said nominal surface plane at each respective location without exceeding said threshold thermal fluence level of the element at said location.
Claim 24
Independent Claim
141 words
A method of texturing a surface of an element comprising the steps of: providing a non-metallic brittle element which has a surface, the surface having a nominal surface plane; directing a plurality of laser pulses at a plurality of locations on the surface of the element, each laser pulse having a fluence f p and a duration t p at a respective location on the surface of the element; the element having a threshold thermal fluence level at each location above which the element shatters and/or results in material ejection; and each laser pulse having a fluence f p and duration t p which is selected to produce a bump of diameter D d and a height h d above said nominal surface plane at each respective location without exceeding said threshold thermal fluence level of the element at said location.
Claim 25
Dependent Claim
39 words
A method of texturing as claimed in claim 21 wherein: a plurality of bumps are formed having substantially the same height, h d ; and each bump is a smoothly shaped dome free of surface cracks and material ejection.
Claim 26
Dependent Claim
37 words
A method of texturing as claimed in claim 22 wherein: the height h d of each bump is from 1 to 1,000 nanometers; and the diameter D d of the bump is from 1 to 200 micrometers.
Claim 27
Dependent Claim
42 words
A method of texturing as claimed in claim 23 wherein each said spaced apart location is separated from a nearest neighboring spaced part location by a center to center spacing distance D s ≧D d which is from 1 to 500 micrometers.
Claim 28
Dependent Claim
43 words
A method of texturing as claimed in claim 24 wherein the duration t p is from 10 -9 to 10 -1 seconds and the laser pulse has a spot size D p at each respective location which is from 1 to 500 micrometers.
Claim 29
Dependent Claim
17 words
A method of texturing as claimed in claim 25 wherein the element is composed essentially of glass.
Claim 30
Dependent Claim
79 words
A method of texturing as claimed in claim 21 wherein: a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and said plurality of laser pulses have a pulse repetition rate F p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
Claim 31
Dependent Claim
17 words
A method of texturing as claimed in claim 21 wherein the element is composed essentially of glass.
Claim 32
Dependent Claim
79 words
A method of texturing as claimed in claim 28 wherein: a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and said plurality of laser pulses have a pulse repetition rate F p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
Claim 33
Dependent Claim
39 words
A method of texturing as claimed in claim 28 wherein: a plurality of bumps are formed having substantially the same height h d ; and each bump is a smoothly shaped dome free of surface cracks and material ejection.
Claim 34
Dependent Claim
37 words
A method of texturing as claimed in claim 30 wherein the element strongly absorbs laser energy in a first spectral region and the laser pulse has a wavelength λ p which is in said first spectral region.
Claim 35
Dependent Claim
41 words
A method of texturing as claimed in claim 31 wherein said laser pulse has a wavelength λ p which causes penetration of the laser pulse into the element at each location on the surface from 10 -8 to 10 -3 meters.
Claim 36
Dependent Claim
25 words
A method of texturing as claimed in claim 32 wherein each laser pulse causes near surface heating which melts the element at each respective location.
Claim 37
Dependent Claim
37 words
A method of texturing as claimed in claim 30 wherein: the height h d of each bump is from 1 to 1,000 nanometers; and the diameter D d of each bump is from 1 to 200 micrometers.
Claim 38
Dependent Claim
43 words
A method of texturing as claimed in claim 34 wherein the duration t p is from 10 -9 to 10 -1 seconds and the laser pulse has a spot size D p at each respective location which is from 1 to 500 micrometers.
Claim 39
Dependent Claim
79 words
A method of texturing as claimed in claim 35 wherein: a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and said plurality of laser pulses have a pulse repetition rate F p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
Claim 40
Dependent Claim
37 words
A method of texturing as claimed in claim 35 wherein the element strongly absorbs laser energy in a first spectral region and the laser pulse has a wavelength λ p which is in said first spectral region.
Claim 41
Dependent Claim
41 words
A method of texturing as claimed in claim 37 wherein said laser pulse has a wavelength λ p which causes penetration of the laser pulse into the element at each location on the surface from 10 -8 to 10 -3 meters.
Claim 42
Dependent Claim
25 words
A method of texturing as claimed in claim 38 wherein each laser pulse causes near surface heating which melts the element at each respective location.
Claim 43
Dependent Claim
79 words
A method of texturing as claimed in claim 39 wherein: a plurality of laser pulses are directed at each of at least some of the locations for increasing the height of each bump at said each of at least some of the locations; and said plurality of laser pulses have a pulse repetition rate F p which is selected so that said threshold thermal fluence level is not exceeded at said each of at least some of the locations.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 7.5 Years (Year 8) | 2003-10-22 | 2004-04-22 | 2004-10-22 | $3760.00 | Window Closed / Lapsed |
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